[Chicken-users] Starting up spiffy for dynamic content

[Norman Gray]

Greetings.

I'm having difficulty working out how to start spiffy, to serve entirely 
dynamic content.  I feel sure I'm missing something really obvious.

I want to serve entirely dynamic content; that is, no static file 
content, but with me supplying code which turns a request structure into 
a response structure.

The spiffy documentation at <http://wiki.call-cc.org/eggref/4/spiffy> 
describes clearly how to do all of the configuration necessary to 
configure the server and start it, and mentions in passing that it may 
be necessary to use accept-loop rather than start-server... and so on.

But it doesn't have what I was looking for, namely a description of a 
dispatcher of some type, which might hand off to handler functions 
depending on the structure of the incoming URI, but which would at least 
let me interpose my own handler.  If such a thing exists, I would have 
expected it to be documented in the section 'Starting the server'.

Looking at spiffy.scm, where I'd expect to see this handler is inside 
handle-incoming-request, around where the compiled-vhost-map is 
consulted, or _possibly_ inside process-entry, though the latter appears 
to be very much a filesystem-walker.

If the content of handle-incoming-request included

(handle-exceptions exn
    (begin ...)
  (if (dispatcher)
      ((dispatcher) (current-request))
      (let ((host (uri-host (request-uri (current-request)))))
        ....

then the parameter (dispatcher) could naturally take control at this 
point.

It occurred to me that I could/should use the vhost-map to do this 
dispatching, using something like

(vhost-map `((".*" . ,(lambda (continue) ... and ignore (continue)))))

But (a) that would clearly be a hack, and (b) it appears that that's 
designed to be able to re-parameterise a request, rather than handle it 
itself, so (c) that would clearly be a hack.

Another possibility is to specify the handle-not-found handler, and make 
sure to start the spiffy server in a context which has no files at all, 
so that the handle-not-found handler will always be called.  But that 
also feels like a bit of a hack.

The final possibility is to use intarweb directly, but that's 
unappealing, since it would require me cut-and-pasting quite a lot of 
the content of spiffy.scm.

Where this is coming from: I'm pretty familiar with the Racket servlet 
framework which requires, in serve/servlet 
<http://docs.racket-lang.org/web-server/run.html>, a request->response 
mapping function.

If I'm missing something really obvious, then apologies, and could 
someone hand me the clue-stick?

Best wishes,

Norman


--
Norman Gray  :  https://nxg.me.uk
SUPA School of Physics and Astronomy, University of Glasgow, UK